WASHINGTON — Saddam Hussein’s intelligence agency secretly financed a trip to Iraq for three U.S. lawmakers during the run-up to the U.S.-led invasion, federal prosecutors said Wednesday.

An indictment in Detroit accuses Muthanna Al-Hanooti of arranging for three members of Congress to travel to Iraq in October 2002 at the behest of Saddam's regime. Prosecutors say Iraqi intelligence officials paid for the trip through an intermediary.

Al-Hanooti was charged with conspiracy to act as an unregistered agent of a foreign government, illegally purchasing Iraqi oil and lying to authorities.

Al-Hanooti worked on and off from 1999 to 2006 as a public relations coordinator for Life for Relief and Development, a Michigan group formed after the first Gulf War to fund humanitarian work in Iraq.

But prosecutors said he also was responsible for monitoring Congress for the Iraqi Intelligence Service. From 1999 to 2002, he allegedly provided Saddam’s government with a list of U.S. lawmakers he believed favored lifting economic sanctions against Iraq.

A Justice Department official told NBC News that the agency is satisfied that the three members of Congress had no idea that Saddam's intelligence service was behind the trip.

The lawmakers are not mentioned but the dates correspond to a trip by Democratic Reps. Jim McDermott of Washington, David Bonior of Michigan and Mike Thompson of California. There was no indication the three lawmakers knew the trip was underwritten by Saddam.

“Obviously we didn’t know it at the time,” McDermott spokesman Michael DeCesare said Wednesday. “The trip was to see the plight of the Iraqi children. That’s the only reason we went.”

Church invited us, spokesman saysDeCesare said McDermott was invited to go to Iraq by a Seattle church group and was unaware of any other funding for the trip.

During the trip, the lawmakers expressed skepticism about the Bush administration’s claims that Saddam was stockpiling weapons of mass destruction. Though such weapons ultimately were never found, the lawmakers drew criticism for their trip at the time.

Oklahoma Sen. Don Nickles, the second-ranking Senate Republican at the time, said the Democrats “sound somewhat like spokespersons for the Iraqi government.”

The Associated Press and NBC News' Pete Williams contributed to this report.